Transducer



Feb. 5, 1957 I c. F. JENSEN TRANSDUCER Filed March 25, 1952 56 Q INVENTOR.

BY MXMMMRMM/ handling.

United States Patent() TRNSDUCER i iClarence E. Jensen, 5 Racinejf Wis.; 'assignor 1' to ."Webster .f` Electric lCompany, `Raciney'Wis., a corporation `of Deiau v-ware Application 'March 25, 1952, Serial Nof2785442 6=Glaims.r' :(Cl.' f1-'79100.41)

" Thisinv'entionrelates to an electromechanical trans duce'runit and more particularly to a transducer 'unit utilizing aceramic transducer element for the reproduc- Ytion' of sound-from records.

Accordingly one object of this Ainvention isto ,provid'e a new and improved transducer unit which is constructed to prevent theapplicationof undesirable rforces to a transducer element in the unit.

Another Yobject is to provide a new-y and improved mounting for astylus ina transducer unit.

In accordance withl these and many vother objects, one

embodiment of theV invention comprises a transducer `unit having a housing in which apairsof. internal intersecting Arecesses are formed. Astylus holdenis `iposit'ionedwit'hin oneV of these recesses and extends upwardly and rearwardly at a first predetermined acute angle. The holder is supportedl at its upper end by a resilient mounting bloc,k,'and it is engaged intermediate its endsbya damp- V 'ing block. A flexible ceramic transducer element positioned within the other recess is .rigidly secured to the stylus holder adjacent its front end, and it extends rearwardly therefrom in a substantially horizontal direction. A' pair of electrically` conductive stripssare connected to the element at a point within the housingspaced. from the'stylus holder to provide a means for conductingfthe voltage variationsvproduced by the element to yan external reproducing system.

VOther'objects and advantages of the present. invention will becomeapparent from a consideration ofthefollowing specification when taken in conjunction with the drawings wherein:

Fig. 1 is a side yelevational view of a transducer unit constructed in accordance Withthis'invention showing amounting structure therefore;

Fig. 2 is a Vtop plan view of the transducer unit shown 'C in Fig. l;

.'Fig. 3k is a vertical cross sectional view taken centrally of the transducer-.unit-shown in- Fig. 2; and

Fig. 4 is a bottom plan view of the transducer unit shown inFig. y1 lwithout the supporting structure.

V.2,780,680 Patented Feb..5, 1957 ICC 'JI-12 and 14 by the rivets; 16 to provide a means lfor, mount- ,ing the unit '10-in a tone or pick-up arr (not shown).

The housing members 12 and 14 and the `brackets'20 are `preferably*fabricated yfrom -any suitable lightweight dielectric material.

The housing. member -12, which is a mirror imagelof vthe' member 14, has a pair'o'f intersecting recesses -y24 and 26'forme'd therein. A recess 28 is formed in -the member' t12 projecting outwardly from ther-ccess A24 at alright anglefthe'reto. A slot 29 is formed in they-member 12 'transverse to the recess '28, and the-lower surface of the vslot 29 isidepressed below the level'ofthe bottom surface of the-recess24. A- block 30 of. resilient damping material suchV as rubber, having anaperturef3`2 therethrough is vpositioned within the recess 28 andthe slot 29,"and Vis ofs'uchhieight as to be slightly compressed "by 'the 'two members 12- and `14 iwhen these members are VSecured together by the rivets 16 in anassembled 'face-toiface relationship. A vertical wall 34 alt the slot 20:"29gp`revents'-the blocktl from being displaced from the 'reces's'ZS andlslo't 29 when this block is 'subjected to external forces.

Atubularstylusholder orchuck 36 is positioned `with inl'the recess24.l It is formed with a right angle bend movably'm'ounted within ther aperture 32 inthe mountjing block. A mass lof material37, such as 'liquid solder,

"- is'iiplied tothe chuck -36 at the end thereof projecting out ofthe vblockl. This mass of vmaterial 37 prevents the chuck36 from being. displacedyfromthe aperture 32"but,permits thechuck' to pivot therein. `The lower "endof the chuck 136 is swaged orotherwiseatteed --Tren'iovablyto're'ceive therein a stylus 38- having a :tip 40 projecting outwardly from the unit 10 to .engage the .grooves in a record (not shown). Thestylus andgstylus 35 holder may be considered as constituting a stylusstructure and. while the described construction is preferred theltwo can be made in one piece.

A block. 42 of damping material is secured within a recess 44 in the member 12. to project outwardly therefrom and engage the 'flattened' portion of the chuck f36 approximately midway along the inclined lengththereof. A-similar recess 44 in the member14 engages the upper half of the block 42 when the members -12 and 14 'are assembled. The block 442 both prevents unde- -sired'vibrations of the chuck 36 and also resiliently cushions the chuck and stylus 38 against shocks occasioned "by dropping the .transducerunit 10.

A `flexible transducer element 46 comprising apair of laminated ceramic strips 48 isrigidly secured tothe stylus chuck'36 adjacent the stylus v-point 38 by a mass '56 of suitable liquid solder. The element 46 .extends rearwardly and slightly upwardly within the recess :26 from the point at which it is secured to. the chuck y36 vatan acute angle lfrom lthe horizontal which is substantially -smaller than the acute angle formed by the stylus chuck 36' relative to horizontal. The upper. end` of the `element 46 is received ybetween a pair of plates. 52:0f resilient damping material, one of whichl plates isvpositioned ineach of the 'members `12 and 14. adjacent-.the

'upper extremity of the recess 26.

A portion of each of the plates 52 indicated at A54 is recessed' below the ,upper surface to receive a strip t56 'of electricallyconductivel` material which is vintegralwith a terminal"unitindicated generally as'58.` The strips extend vertically upward from the point at which they contact the strips 48 through a pair of odset recesses 62 formed in the members 12 and 14. Enlarged portions 64 of the terminals 58 are disposed Within recesses 66 formed in the members 12 and 14 and extend horizontally outward therefrom to form a pair of sleeves 60. The sleeves 60 provide an easy means for connecting external electrical conductors (not shown) to the transducer unit 10. Each of the terminal units S is secured in position in one of the members 12 and 14 by a tongue 68 formed in these members which cooperates with a groove 7d formed in the lower edge of each of the enlarged portions 64. A dielectric block 72 having a groove 74 in the lower surface thereof which cooperates with the tongue 68 is interposed between the two terminal units 58 to prevent a short circuit between these two terminal units.

Since the transducer element 46 is rigidly secured to the stylus chuck 36 at one end and resiliently engaged at its other end by the plates 52, this element is protected from breakage during the application of any severe stressing forces such as would be produced by dropping the transducer unit 10 onto a record or supporting standard. During the application of any such undesirable forces, the stylus chuck 36 tends to deect in a clockwise direction against the resilient action of the damping block 42, and the resiliently supported end of the element 46 moves slightly with respect to the plates 52 so that the applied force is dissipated both in liexing the stylus chuck 36 and in compressing the resilient blocks 30 and 42. Not only is the -construction of a character to stand up well in use, but it is relatively simple and compact in construction, and it may be assembled readily.

It is to be understood that the above described embodiment'of the invention is merely illustrative of the principles thereof and that numerous other modifications may be devised by those skilled in the art which will fall within the spirit and scope of `this invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A transducer comprising stylus structure inclined upwardly from horizontal, resilient mounting means for the upper end of said stylus structure, a transducer element rigidly secured to the stylus structure adjacent its lower end and extending away from said structure to form an acute angle, and station-ary damping means engaging the upper side of said stylus structure intermediate its ends and xedly mounted in said housing whereby said damping means resists upward deiiection of said stylus structure.

2. A transducer comprising a housing having a pair of intersecting recesses therein, a iirst `of said recesses positioned adjacent the lower edge of the housing and opening out of said housing, a second of said recesses extending upwardly into the housing above said first recess and terminating in a third recess positioned at right angles to and extending downwardly from said second recess, a damping member having .a downwardly extending aperture therein positioned within said third recess, a substantially straight stylus structure in said second recess and having a downwardly bent upper end positioned within said aperture, a transducer element secured to the lower end of the stylus structure and positioned within the rst recess, and means in said first recess for supporting the element at a point spaced from the stylus.

3. A transducer comprising a housing having a pair of intersecting recesses therein, a first of said recesses positioned adjacent one edge of the housing and opening out rst. recess, means carried by said housing for supporting i the other end of said element against movement at a point within said recess spaced rearwardly from the stylus structure, said stylus structure defining an opening at itsv lower end, a record engaging tip removably mounted in said opening and constituting an extension of the lower end of said stylus structure, a fourth recess opening into said second recess intermediate its ends, and a damping block mounted in said fourth recess and engaging the upper 'side of said stylus structure for damping and resisting upward deflection of said stylus structure.

4. A transducer unit comprising a housing having an inclined recess therein, said housing having a second re- ,f cess formed therein in communication with the inclined? recess and extending downwardly therefrom, resilient'` means positioned in the second recess, stylus structurez. positioned in the inclined recess and having a depending; angularly displaced end mounted in the resilient means, and damping means mounted in the housing above the stylus structure at a point spaced downwardly from thfve displaced' end thereof, said damping means having 'ia lower side abutting against the upper side of said styl 1s structure and an upper side abutting againstthe houts-v ing, thereby to damp and to resist upward deilection f the stylus structure. j

5. A transducer unit comprising a housing; an assem-F` bly mounted in said housing comprising an elongated, transducer element having one end secured to said housing and an elongated stylus holding structure positioned at an angle to said element and having a pivotal support at one end securedto said housing and means xedly connecting said holding structure to the other end of said transducer element whereby said element and structure constitute a unitary assembly, and a stylus removably secured to the other end of said stylus holding structure.

6. A transducer comprising a supporting member, stylus holding sturcture extending upwardly from horizontal at a first predetermined acute angle, means for resiliently securing the upper end of said structure to said supporting means, a transducer element coupled to the structure adjacent the lower and free end thereof and extending upwardly from the horizontal at an acute angle smaller f than said rst predetermined angle, and damping means disposed at said stylus structure and abutting against the upper side of the stylus structure and against the supporting member to damp and to resist upward deection of said vstylus structure.

References Cited in the file of this patent UNITED STATES PATENTS 2,567,105 Dreisbach Sept. 4, 1951 2,575,999 Cordes Nov. 20, 1951 2,594,948 Lynch Apr. 29, 1952 2,650,953 Gunter Sept. 1, 1953 FOREIGN PATENTS 615,979 Great Britain Jan. 14, 1949 

